[PyQt] Exceeding max C/C++ int value in signal causes value corruption - most elegant workaround?

[Damon Lynch]

Hello,

Using PyQt 5.4.1 and python 3.4.3 on an amd64 Ubuntu 15,04, I have run 
into a bug in my code 
<http://bazaar.launchpad.net/%7Edlynch3/rapid/zeromq_pyqt/view/head:/rapid/rapid.py#L125> 
where an int value being sent out in a signal is being erroneously 
received as a negative value when it is greater than the maximum int 
value in C/C++ 
<http://stackoverflow.com/questions/13795758/what-is-sys-maxint-in-python-3> 
on the same platform.

For instance, the max int value in C/C++ on my machine is 2147483647. 
When my python code emits a signal with an int value less than that, 
it's received fine. More than that, and the received value is wrong, 
e.g. emit 2153451441 and it is received as -2141515855.

Needless to say when writing my code I had never considered the 
possibility of this bug because in python 3 there is no maximum integer 
size.

What is the most pythonic, elegant and efficient way to work around this 
problem? Off the top of my head I could convert the int to bytes, and 
convert it back again once received, but perhaps there is a better way 
to emit the signal? The docs 
<http://pyqt.sourceforge.net/Docs/PyQt5/signals_slots.html> say 'If an 
argument doesn’t have a corresponding C++ type then it is wrapped in a 
special C++ type that allows it to be passed around Qt’s meta-type 
system while ensuring that its reference count is properly maintained.' 
Should  I instead simply bundle the signal's values into a Python class 
and emit that?

Thanks!
Damon

-- 

http://www.damonlynch.net

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.riverbankcomputing.com/pipermail/pyqt/attachments/20150606/ff23b0f1/attachment.html>